[PATCH] UefiCpuPkg PiSmmCpuDxeSmm: Remove redundant code to set IDT range to RO

[PATCH] UefiCpuPkg PiSmmCpuDxeSmm: Remove redundant code to set IDT range to RO

[Star Zeng]

AllocateCodePages() is used to allocate buffer for IDT range,
the code pages will be set to RO in SetMemMapAttributes(),
then the code to set IDT range to RO in PatchGdtIdtMap() is
redundant and could be removed.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Star Zeng <star.zeng@intel.com>
---
 UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
index 16664f304cde..2a4a29899862 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
@@ -803,11 +803,10 @@ PatchGdtIdtMap (
 
   BaseAddress = gcSmiIdtr.Base;
   Size = ALIGN_VALUE(gcSmiIdtr.Limit + 1, SIZE_4KB);
-  SmmSetMemoryAttributes (
-    BaseAddress,
-    Size,
-    EFI_MEMORY_RO
-    );
+  //
+  // The range should have been set to RO
+  // if it is allocated with EfiRuntimeServicesCode.
+  //
   SmmSetMemoryAttributes (
     BaseAddress,
     Size,
-- 
2.7.0.windows.1

Re: [PATCH] UefiCpuPkg PiSmmCpuDxeSmm: Remove redundant code to set IDT range to RO

[Yao, Jiewen]

Reviewed-by: Jiewen.yao@intel.com.

> -----Original Message-----
> From: Zeng, Star
> Sent: Friday, January 12, 2018 4:02 PM
> To: edk2-devel@lists.01.org
> Cc: Zeng, Star <star.zeng@intel.com>; Yao, Jiewen <jiewen.yao@intel.com>;
> Wang, Jian J <jian.j.wang@intel.com>; Dong, Eric <eric.dong@intel.com>; Laszlo
> Ersek <lersek@redhat.com>
> Subject: [PATCH] UefiCpuPkg PiSmmCpuDxeSmm: Remove redundant code to
> set IDT range to RO
> 
> AllocateCodePages() is used to allocate buffer for IDT range,
> the code pages will be set to RO in SetMemMapAttributes(),
> then the code to set IDT range to RO in PatchGdtIdtMap() is
> redundant and could be removed.
> 
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Star Zeng <star.zeng@intel.com>
> ---
>  UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
> b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
> index 16664f304cde..2a4a29899862 100644
> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
> @@ -803,11 +803,10 @@ PatchGdtIdtMap (
> 
>    BaseAddress = gcSmiIdtr.Base;
>    Size = ALIGN_VALUE(gcSmiIdtr.Limit + 1, SIZE_4KB);
> -  SmmSetMemoryAttributes (
> -    BaseAddress,
> -    Size,
> -    EFI_MEMORY_RO
> -    );
> +  //
> +  // The range should have been set to RO
> +  // if it is allocated with EfiRuntimeServicesCode.
> +  //
>    SmmSetMemoryAttributes (
>      BaseAddress,
>      Size,
> --
> 2.7.0.windows.1